Could I get jail time for this? I'm so scared.?

I work at a Pick N' Save as well as two other jobs. I'm a 19 year old female who has never been in trouble with the law before. I have had so many personal issues going on in my life, and such a full work week schedule it was very hard to bear. I worked as a cashier and today they arrested me on the spot and I had no idea why. No warnings, no talks with managers, they just arrested me. They took me to the car and told me I was being charged with retail theft. I never stole anything. They told me I had been letting customers items that did not scan properly slide, and I would be charged and have to pay back every last item that I missed. I know I was absent minded for the last month and not paying as close attention as I should be. I got taken to jail, photographed, and finger printed. I never took any items for myself from the store. EVER. I had no intention of stealing. They told me I could be facing jail time. I'm so confused and afraid. How long will I be in jail...?